I purchased some cordless headphones a while back on eBay. Two comments:
1) eBay needs to have a non-smoking symbol for products. These bitches smelled like smoke for a month after I got them, and I think it discolored some of the rubber on them. I would never buy from a smoker for any product that I am going to wrap around my head.
2) The brand is InfraSound and it basically has an ifrared base that transmits to the headphone with receivers on either ear. The work ok, but they seem to be getting interference from my monitor, and GOD forbid if I turn my head the wrong direction or raise my hand to adjust the volume (which is located on the bottom side of the ear) and block the receiver... whole fuzz sound, batman. You would think that they could cancel out the fuzz and not bust your ear drums every time the signal cannot be received.

Anyways, don't waste your money if Smoky Smokerton from Smokerville is trying to sell you some cordless infrared headphones, it will be money poorly spend.